code:
#include <bits/stdc++.h>
using namespace std;
const int N = 210;
int n, q;
struct node{
    int v, w;
    node(int x, int y) {v = x, w = y;}
};
vector<node>e[N];
int f[N][N], sum[N];

void dfs(int u, int fa){
    for(int i = 0;i < e[u].size();i++){
        // cout << 1 << endl;
        int v = e[u][i].v, w = e[u][i].w;
        if(v == fa)continue;
        dfs(v, u);
        sum[u] += sum[v] + 1;

        for(int j = min(q, sum[u]);j >= 1;j--){
            // cout << 1 << endl;
            for(int k = min(j - 1, sum[v]);k >= 0;k--){
                // cout << 1 << endl;
                f[u][j] = max(f[u][j], f[u][j - k - 1] + f[v][k] + w);
                //状态转移 关键一步
            }
        }
    }
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    cin >> n >> q;
    for(int i = 1;i <= n - 1;i++){
        int x, y, w;
        cin >> x >> y >> w;
        e[x].push_back(node(y, w));
        e[y].push_back(node(x, w));
    }   
    // cout << e[1][0].v << endl;

    dfs(1, 0);
    cout << f[1][q];
    return 0;
}